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Revised National Ambient Air Quality Standards for Lead EPA Region 4 Ambient Air Monitoring Impacts. Overview. On October 15, 2008, EPA strengthened the national ambient air quality standards (NAAQS) for lead (Pb) to increase protection of public health and the environment.
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Revised National Ambient Air Quality Standards for LeadEPA Region 4 Ambient Air Monitoring Impacts
Overview • On October 15, 2008, EPA strengthened the national ambient air quality standards (NAAQS) for lead (Pb) to increase protection of public health and the environment. • Since 1978, ambient air lead standards have been set at 1.5 μg/m3 (micrograms per cubic meter of air). • Now,EPA is strengthening the lead standards by 90 percent to a level of 0.15 μg/m3. • The level is based on the concentration of lead in total suspended particles (TSP) • EPA is also making changes to the lead monitoring network to ensure monitors are assessing air quality in areas that might violate the new standard. • EPA followed the advice of the Clean Air Scientific Advisory Committee (CASAC) to set the standard no higher than 0.20 μg/m3
Ambient Air Monitoring Implications For EPA Region 4 • Lead monitoring required: • At sources emitting 1.0 tons/year or more of lead based on NEI or other justifiable data. • In core-based statistical areas (CBSAs) with population over 500,000. • EPA OAQPS estimates 236 new or relocated monitoring sites will be required nationwide based on the 2002 NEI and 2007 population estimates. • 40 of these new or relocated monitoring sites are in Region 4 • If additional sources over 1.0 ton/year from the 2006 Toxics Release Inventory (TRI) are included, the number of required new or relocated sites increases to 72. • Currently, a total of 25 lead monitoring sites are operating in five states in Region 4.
EPA Region 4 Lead Monitors 1 TRI sources do not include sources listed as over 1 ton/year in the NEI
Ambient Monitoring Network Implementation • At least half of required monitors must be operating by January 1, 2010. Also, source-oriented monitors must be installed before population-oriented monitors. • Source-oriented monitors must be identified in the 2009 annual monitoring network plans due July 1, 2009. • The second half of the required monitors must be operating before January 1, 2011. • These monitors must be identified in the periodic network assessment plans due July 1, 2010.
Ambient Monitoring Methods • EPA retains the current indicator based on measuring lead in the air using total suspended particles (TSP) monitors, reflecting evidence that lead particles of all sizes pose health risks. • EPA will allow the use of lead-PM10 monitoring instead of lead-TSP monitoring in only certain limited circumstances • Lead-PM10 low-volume monitoring would be allowed where: • Lead is not expected to occur as large particles; and • A monitoring agency can demonstrate that lead concentrations are not expected to have three-month averages greater than or equal to 0.1 μg/m3 • If a lead-PM10 monitor measures three-month levels greater than or equal to 0.1 μg/m3, then the monitoring agency would have to install and operate a lead-TSP monitor within six months • Lead- PM10 measurements greater than the NAAQS violate the standard. • Most of the population-oriented required sites are anticipated to meet the requirements for using Pb-PM10 samplers.
Sources Contributing to Lead Pollution • More than 1,300 tons of lead are still emitted each year from about 16,000 sources, many of which emit a fraction of a ton • The highest levels of lead in air are generally found near lead smelters • Other sources of current lead emissions include: • Iron and steel foundries • Copper Smelting • Metal mining • Industrial/commercial/utility boilers • Gasoline for small planes (not used in commercial passenger aircraft) • Waste incinerators • Cement manufacturing • Glass manufacturing • Lead particles emitted into the air from these and other sources can end up in water, soil and dust, and over time can re-enter the air • This cycling of lead in the environment means people can be exposed to lead that was emitted just yesterday or years ago